Semiconductors, or computer chips, are found in virtually every electrical product manufactured today. Chips are used not only in very sophisticated industrial and commercial electronic equipment, but also in many household and consumer items such as televisions, clothes washers and dryers, radios, and telephones. As products become smaller but more functional, there is a need to include more chips in the smaller products to perform the functionality. The reduction in size of cellular telephones is one example of how more and more capabilities are incorporated into smaller and smaller electronic products.
As electronic products become increasingly miniaturized, it is desirable to combine several chips into a single system package. By combining what were previously separate and distinct chips into a single package, manufacturing costs can be greatly reduced. Although preferable, the integration of chips or other circuitry formed using thin film processing techniques on wafers with other chips and packages can present many challenges. For example, today's thin-film manufacturing processes require the use of expensive, specialty substrate materials when forming wafer-level packages. Although a PCB may be used as a substrate, they are relatively delicate and may be damaged by the high temperatures used during thin-film processing. Also, in today's wafer-level package devices, any connected IC chips are generally limited to a 2D layout configuration. As a result, the number of IC chips that can be coupled directly to a substrate is greatly limited in accordance with the geometry of that substrate. Furthermore, because the chips or dies are generally mounted over tape or Copper (Cu) foil, inter-wafer, and intra-wafer registration variation of die mounted on the wafer is significant and negatively impacts system performance.
In many applications, it is desirable to achieve wafer level package integration with one or more semiconductor devices. The interconnect between the semiconductor die has been achieved with through hole conductive vias or through hole plating and redistribution layers (RDL). However, the formation of the interconnect structure, including RDLs, is typically performed on an organic substrate having a low glass transition temperature (Tg). The substrate Tg is typically less than 200° C., which limits processing options for the interconnect structure.